Radial turbine engines, and particularly larger radial turbine engines with a radial inflow turbine, pose a different challenge compared to axial turbine engines. The radial inflow turbine already has a comparatively large diameter relative to comparable axial turbine engines but requires additional structure with a still larger diameter for the static components.
These static components include nozzle guide vanes for directing the hot combustion gases into the turbine inlet, and mechanical structure which fixes the centricity and clearance between the coupled compressor and turbine components.
In smaller turbine engines with less radial extensions, and indeed with lower turbine inlet temperatures, simpler designs are being used. But larger, advanced radial turbines with turbine inlet temperatures of 1000 degrees C. and higher require the special solutions described in this disclosure in order to avoid or mitigate distortions and excess displacements due to differential thermal radial expansion and/or contraction and, as a consequence, leakage and loss of engine performance.